Cold storage carton

ABSTRACT

Container for holding material during storage or transportation in which the separable, insulated cover contains a body of heatabsorbing substance thermally exposed to the interior of the container through a heat-conducting inside face of the cover, the cover being capable of being formed from a single piece of fiberboard or other sheet material.

United States Patent Cornish et al.

[54] COLD STORAGE CARTON [72] Inventors: Edward Cornish; Harold R. Liebherr,

both of Maumee, Ohio [73] Assignee: Cornish Containers, Inc.

[22] Filed: July 20, 1970 [21] Appl. No.: 56,327

[52] U.S. Cl.. ..62/37l, 62/457 [51] Int. Cl ..F25d 3/08 [58] Field olSearch ..62/457, 372,371,437; 165/73 [56] References Cited UNITED STATES PATENTS 2,024,082 12/1935 Woodruff ..62/457 X 51 July 25, 1972 2,087,966 7/1937 Clark ..62/457 3,545,230 12/1970 Morse ....62/530 2,850,885 9/1958 Mohretal. ..62/372 Primary Examiner- William Wayner Attorney-John W. Overman [57] ABSTRACT Container for holding material during storage or transportation in which the separable, insulated cover contains a body of heat-absorbing substance thermally exposed to the interior of the container through a heat-conducting inside face of the cover, the cover being capable of being formed from a single piece of fiberboard or other sheet material.

9 Claims, 3 Drawing Figures COLD STORAGE CARTON This invention relates to self-contained cold storage cartons of the kind used for shipping food stuffs and other products that have to be maintained at low temperature and especially of the kind used for transporting packaged frozen food.

Previous devices of this kind were often made in the form of shipping containers or cartons having a compartment to receive a heat-absorbing medium such as brine, usually contained in a metal or plastic flask or other container. The carton was dismantled or partially disassembled to remove or replace the container of heat-absorbing medium. This not only required additional labor but created the danger of losing or misplacing the container at the packing station or unpacking location. A metal or plastic container might be dented or punctured when being removed and replaced, resulting in the escape of the heat-absorbing medium or, if a puncture were not discovered in time, might result in leakage of the medium into the contents of the carton, spoiling what are usually rather costly packaged foods.

The object of the present invention to provide a cold storage shipping container which is self-contained in that the refrigerating medium is an integral part of the carton.

It is another object to provide the cooling medium in a separable wall such as a cover or lid of the carton so that when desired this part of the carton with the cooling medium may be separately placed in the freezing compartment of a cold storage room or warehouse to be. brought down to the desired low temperature.

It is another object of the invention to provide such a carton which is reusable without dismantling other than the otherwise necessary removal of the cover or lid; a carton that may be packed with the articles to be transported while at the same time the heat-absorbing medium is being cooled; and a carton in which the container for the heat-absorbing medium is protected against accidental damage in use of the carton or when the cover is being handled, stored or cooled. Another object of the invention is to provide such a container with a simple cover which fits the open side of the container, as by simply being dropped into a rabbet surrounding the opening, without the need for any fluid-tight seals, threaded fittings or the like.

Other objects of the invention are to provide a carton cover which is simply and inexpensively formed of fiberboard, chipboard, corrugated paper or boxboard or the like, but will be self-contained and bonded into an integral one-piece panel that is abuse-resistant, an effective thermal insulator, and light in weight so as to be easily handled at the packing and unpacking locations.

The invention is shown in one embodiment in the drawings in which:

FIG. 1 is a perspective view of a carton made according to the invention showing the lid in tilted-up position;

FIG. 2 is a cross section of the carton of the invention taken in the plane ofthe line 22 of FIG. 1; and,

HO. 3 is a perspective view of the cover of the carton of the invention showing the elements in partially assembled relation.

Referring to the drawings, the carton of the invention may be made of ordinary fiberboard or corrugated paper or boxboard formed into hollow side walls 12 and bottom 14. The hollow walls are filled with suitable insulating material, for example fibrous insulation, and preferably foamed-inplace urethane plastic or other insulating plastic foam. The upper ends of the side walls are preferably provided with a rabbet 16 extending most desirably around the inner edges of the four sides of the carton to form a recess into which the cover 18 of the carton fits snugly.

The cover 18 as shown in FIGS. 2 and 3 is made as a hollow panel or completely enclosed envelope. The envelope is of a width and length to close the open side of the carton and is sufficiently thick to receive adequate insulation not only to insulate the interior of the carton from the surrounding atmosphere, but also for an additional purpose to be referred to later.

Preferably the envelope forming the cover is produced from a single piece of fiberboard by folding a sheet of the material to form a top 20, an inner facing 22 and side walls 24. Two of the opposed side walls are extended to form flaps 26, the third side wall is extended to form a flap 28 of somewhat greater width than the other two flaps, and the fourth side wall is extended to form the inside facing 22 of the cover. It is within the present concept to provide such an envelope from several pieces rather than a single piece, although in the interest of increased strength, greater rigidity and ease in assembly, the use of a single piece is preferred.

The inside facing 22 of the carton is provided with a plurality of closely spaced openings 23 therethrough whose aggregate area represents something like 25 to 75 percent of that area of the inside facing of the cover exposed to the interior of the carton.

The cover is fllled with a highly efiicient insulating material preferably polyurethane foam 30, which desirably completely fills the inside of the cover and is provided with one or more recesses 32, which in area represent a substantial proportion, say more than 50 percent of the cross-sectional area of the interior of the carton and in depth approximately one-half of the thickness of the cover. Disposed within the foam insulation and adjacent the top surface of the cover, a steel or other metal fabric or mesh 34 is arranged to provide reinforcement for the cover and to resist loads thereon as when a series of cartons are stacked on top of each other or as when the cover is dropped or accidentally stepped on or in another way subjected to a substantial flexing load.

The recesses in the foamed insulation with the heat-absorbing material in place are covered with a metal sheet 38 such as a light gauge, say 30 gauge, zinc plated steel which is preferably creased along diagonal or other lines as at 40 to increase rigidity. The metal sheet extends beyond the recesses so as to cover the margins of foamed insulation surrounding the recesses on all four sides of the cover. The flap 28 of the one side of the carton is folded down over the metal sheet and the inner facing 22 is over the metal sheet and the flap 28 and adhesively secured to the metal sheet 38 and the flaps 26 and 28 at the three sides of the cover. The openings 23 in the inner facing of the cover expose the metal sheet to the interior of the carton when the cover is in place so that heat within the carton may be transmitted through the metal sheet and into bodies 36 of the heat-absorbing material.

Since the heat-absorbing bodies are received completely within the confines of the cover and are in contact or closely adjacent to the metal plate which in turn faces the interior of the carton, the cooling efficiency of the heat absorber is high and this efficiency is achieved without sacrificing any of the usable volume of the box and without requiring the handling and storage of demountable devices or components.

In assembling the cover of this invention the fiberboard blank to be converted into the cover is suitably cut and then placed in a fixture which folds up the four side walls 24 of the cover and holds the flaps 26 inwardly and to the level of the inner edges of the side walls 24 of the cover. When the metal reinforcing mesh 34 is used, this is laid in the interior of the partly formed cover preferably resting on the inside surface of the top wall of the cover. The open face of the cover is then closed by a suitably shaped platen with: cores located to form thicknesses 32 to be formed in the insulation. The polyurethane foam or other foamed-inplace insulation is injected into the closed space formed between the folded up blank and the platen, the cores being located to form the recesses in desired location and depth in the foam. The foam is preferably one such as polyurethane which adheres tenaciously to paper, fiberboard and other surfaces so that when the foam solidifies it cements together the four side walls 21% of the cover, the top wall 20, and the folded-in flaps 26. The bags of heat-absorbing material are then put in place, the metal sheet placed over them, and the inner facing 22 of the cover folded in and cemented in place. Any suitable adhesive may be used for this purpose but it has been found that ordinary rubber-base contact cement is quite effective.

The cover filled with the foam that adheres to the interior surface of the four side walls, the top wall and to the inwardly turned flaps 26 provides a highly rigid and sturdy unit, especially when the metal sheet is in place and the inner facing of the cover is cemented to the main body of the cover, especially where the cement extends around the three sides of the cover so that the inner facing adheres to the flaps 26 and to the flap 28 to bond the whole assembly together into a unit.

While it has been found that polyurethane foam is highly effective to insulate the cover, and simultaneously body the elements of the cover into an integral panel, other insulations, such as polystyrene foam board, polystyrene bead molded panels, and fibrous insulation may be used in place of the polyurethane foam. If so then it would be desirable to cement the insulation in place to the inside surface of the top wall of the cover and at least to the opposed flaps 26 so as to gain as much rigidity as possible from use of these other insulations as light-weight cores in the cover.

To increase the strength, rigidity and integrity of the cover, it is preferred to employ mechanical fasteners through the cover and holding the top wall and the inside facing securely together against any expanding force of the freezing and thawing of the heat-absorbing medium. Bolts 42 are received in holes 44 in the top cover, the insulation, the metal sheet 38 and the inside facing. Nuts are threaded over the inner ends of the bolts to clamp the assembly together. Since the bolts pass through the part of the top cover backed up by the metal mesh reinforcement 34 and through the regions of the inside facing backed up by the metal sheet 38 the nuts may be drawn up tightly to clamp the opposite facings of the cover securely together.

The bolts are located at opposite sides of and adjacent the recesses 32 so as to best resist any effects of expanding of the bodies 36 of refrigerating medium. The bolts may be made of resinous material such as polycarbonate, nylon or the like if it is desired to eliminate as much as possible the flow of heat that would otherwise occur through metal bolts.

The metal sheet 38 protects the bodies 36 of heat-absorbing medium against contact with sharp edges or pointed objects which might otherwise puncture the plastic film making up the bags containing the heat-absorbing medium. Having good heat conductivity and being exposed through the plurality of openings in the inner facing 22 of the cover permits ready transfer of heat from inside the carton to the heat-absorbing bodies when the carton is filled and being transported. When the covers are removed from the carton and placed in the freezing compartment to have the heat removed from the heat-absorbing medium, the metal sheet in close proximity to the heat-absorbing bodies permits rapid heat transfer from the bodies to the atmosphere in the freezing compartment. After being brought down to desired temperature, the cover need then only be dropped in place in the rabbet around the open end of the carton, although of course suitable latches and any other fastening mans may be employed to secure the cover in place if desired.

The heat-absorbing medium of the present invention is preferably a mixture of water and propylene glycol, the desired proportions of the mixture being percent by volume of propylene glycol and 95 percent by volume of water. This provides a mixture which upon exposure to low temperatures, say from F. to 30 F. forms into a hard or slushy mass which has a high degree of latent heat and at higher temperatures, say above 32 F. would be a liquid. Instead of the glycolwater mixture, the medium may be ordinary brine or water alone, especially where the greatest amount of heat-absorbing capacity is desired. It is preferred to add a small amount of methyl cellulose or like thixotropic agent to the propylene glycol-water mixture, or to the water when used alone, say 5 percent by volume, the proportion being selected so as to be just enough to cause the mixture to gel under normal room temperatures. This is a safeguard against loss of the mixture should the plastic film bag develop a leak as if it should be accidentally punctured. Were this to happen without detection, the water or the glycol-water mixture could leak into the container and contaminate the contents which might be a serious economic loss in the case of some food stufi's. With adequate gelling or thixotropic agent in the liquid, such punctures would not result in the flow of the liquid from the plastic film bag, thereby safeguarding the contents of the carton.

While the propylene glycol mixture containing a thixotropic gelling agent is preferred in the present invention, other heatabsorbing materials such as brine might be employed. These and other modifications may be made within the spirit of the invention as defined by the claims.

We claim:

1. An insulated carton for storing and transporting cooled articles having walls and in which a cover forms one wall of the carton, the cover being hollow and formed by folding a fiberboard blank into a top wall and four side walls, the first and second of which are at opposed sides and terminate as flaps folded inwardly to lie substantially in the plane of the inner face of the cover and the third of which terminates as a flap of a size substantially coextensive with the width and length of the cover so as to form the inner facing of the cover and the fourth of which terminate as a flap of a width to underlie the free outermost margin of the flap forming the inner fac ing, a polyurethane foam in the hollow of the cover and substantially filling the hollow and adhered to the inner surfaces of the outer facing, the side walls and the first and second flaps, a metal mesh reinforcement in said foam underlying in contiguous relation to the top wall of the cover, a recess in the inner face of the body of foam facing the interior of the carton and representing in area a major portion of the area of the opening of the carton normally closed by the cover and being in depth approximately one-half the thickness of the foam, a plastic film bag in said recess containing a mixture of propylene glycol, water, and methyl cellulose in proportions forming a gel at room temperature, a diagonally creased metal sheet overlying the recess and the margins of the foam surrounding the recess to enclose and protect the contents of the recess and immediately underlying the third flap, openings through the third flap exposing the metal sheet to the interior of the carton and representing in aggregate area from 25 to 75 percent of the cross-sectional area of the interior of the carton, an adhesive securing the third flap to the other three flaps, and fasteners extending through the cover and holding the top wall to the inner facing to provide a rigid unitary structure.

2. An insulated carton for storing and transporting cooled articles comprising carton walls and a hollow cover having a top wall and four side walls, and an inner facing of a size substantially coextensive with the width and length of the cover, a foamed plastic in the hollow of the cover and substantially filling the hollow and adhered to the inner surfaces of the wall and of the side walls, a recess in the inner face of the body of foamed plastic facing the interior of the carton and representing in area a major portion of the area of the opening of the carton normally closed by the cover and being in depth less than the thickness of the foam, a heat-absorbing body in said recess covered by said inner facing, and openings through the inner facing exposing the affect of the heat-absorbing body to the interior of the carton.

3. The carton of claim 2 wherein the heat-absorbing material comprises water and methyl cellulose in proportions forming a gel at normal room temperature.

4. The carton of claim 2 wherein the heat-absorbing material is covered by a protective sheet and fastening means secure the sheet to the wall.

5. The carton of claim 2 wherein reinforcement is in the plastic foam adjacent the outer facing.

6. The carton of claim 2 in which the foam plastic in the ho]- low cover is a polyurethane foam having a recess in the foam facing the interior of the carton, a plastic film bag is received in said recess containing a mixture of water and methyl cellu lose in such proportions as to form a gel at normal room temperature, and openings through the inner facing to expose the plastic film bag to the interior of the carton.

7. The carton of claim 6 in which the openings through the inner facing represent in aggregate area from 25 to 75 percent of the cross-sectional area of the interior of the carton.

8. The carton of claim 2 in which the cover is formed by folding a fiberboard blank into a top facing and four side walls, the first and second of which are at opposed sides and terminate as flaps folded inwardly to lie substantially in the plane of the inner face of the cover and the third of which terminates as a flap of a size substantially coextensive with the width and length of the cover so as to form the inner facing of the cover and the fourth terminates as a flap of a width to underlie the free outermost margin of the flap forming the inner facing, and an adhesive secures the third flap to at least some of the other three flaps to provide a rigid unitary structure.

9. An insulated carton for storing and transporting cooled articles comprising side and bottom walls and a removable cover, the cover being hollow and formed by folding a fiberboard blank into a cover outer facing and four cover side walls, the first and second of which are at opposed sided and terminate as flaps folded inwardly to lie substantially in the plane of the inner face of the cover and the third of which terrninates as a flap of a size substantially coextensive with the width and length of the cover so as to form the inner facing of the cover and the fourth terminates as a flap of a width to underlie the free outermost margin of the flap forming the inner facing, a polyurethane foam in the hollow of the cover and substantially filling the hollow and adhered to the inner surfaces of the outer facing, the side walls and the first and second flaps, a recess in the inner face of the body of foam representing in area a major portion of the area of the opening of the carton normally closed by the: cover and in depth less than the thickness of the foam, a heat-absorbing body in said recess, a metal sheet overlying the recess and the margins of the foam surrounding the recess and immediately underlying the third flap to enclose and protect the contents of the recess, openings through the third flap exposing the metal sheet to the interior of the carton and representing in aggregate area from 25 to 75 percent of the cross-sectional area of the interior of the carton, and fasteners securing the third flap to the outer facing to provide a rigid unitary structure. 

1. An insulated carton for storing and transporting cooled articles having walls and in which a cover forms one wall of the carton, the cover being hollow and formed by folding a fiberboard blank into a top wall and four side walls, the first and second of which are at opposed sides and terminate as flaps folded inwardly to lie substantially in the plane of the inner face of the cover and the third of which terminates as a flap of a size substantially coextensive with the width and length of the cover so as to form the inner facing of the cover and the fourth of which terminate as a flap of a width to underlie the free outermost margin of the flap forming the inner facing, a polyurethane foam in the hollow of the cover and substantially filling the hollow and adhered to the inner surfaces of the outer facing, the side walls and the first and second flaps, a metal mesh reinforcement in said foam underlying in contiguous relation to the top wall of the cover, a recess in the inner face of the body of foam facing the interior of the carton and representing in area a major portion of the area of the opening of the carton normally closed by the cover and being in depth approximately one-half the thickness of the foam, a plastic film bag in said recess containing a mixture of propylene glycol, water, and methyl cellulose in proportions forming a gel at room temperature, a diagonally creased metal sheet overlying the recess and the margins of the foam surrounding the recess to enclose and protect the contents of the recess and immediately underlying the third flap, openings through the third flap exposing the metal sheet to the interior of the caRton and representing in aggregate area from 25 to 75 percent of the cross-sectional area of the interior of the carton, an adhesive securing the third flap to the other three flaps, and fasteners extending through the cover and holding the top wall to the inner facing to provide a rigid unitary structure.
 2. An insulated carton for storing and transporting cooled articles comprising carton walls and a hollow cover having a top wall and four side walls, and an inner facing of a size substantially coextensive with the width and length of the cover, a foamed plastic in the hollow of the cover and substantially filling the hollow and adhered to the inner surfaces of the wall and of the side walls, a recess in the inner face of the body of foamed plastic facing the interior of the carton and representing in area a major portion of the area of the opening of the carton normally closed by the cover and being in depth less than the thickness of the foam, a heat-absorbing body in said recess covered by said inner facing, and openings through the inner facing exposing the affect of the heat-absorbing body to the interior of the carton.
 3. The carton of claim 2 wherein the heat-absorbing material comprises water and methyl cellulose in proportions forming a gel at normal room temperature.
 4. The carton of claim 2 wherein the heat-absorbing material is covered by a protective sheet and fastening means secure the sheet to the wall.
 5. The carton of claim 2 wherein reinforcement is in the plastic foam adjacent the outer facing.
 6. The carton of claim 2 in which the foam plastic in the hollow cover is a polyurethane foam having a recess in the foam facing the interior of the carton, a plastic film bag is received in said recess containing a mixture of water and methyl cellulose in such proportions as to form a gel at normal room temperature, and openings through the inner facing to expose the plastic film bag to the interior of the carton.
 7. The carton of claim 6 in which the openings through the inner facing represent in aggregate area from 25 to 75 percent of the cross-sectional area of the interior of the carton.
 8. The carton of claim 2 in which the cover is formed by folding a fiberboard blank into a top facing and four side walls, the first and second of which are at opposed sides and terminate as flaps folded inwardly to lie substantially in the plane of the inner face of the cover and the third of which terminates as a flap of a size substantially coextensive with the width and length of the cover so as to form the inner facing of the cover and the fourth terminates as a flap of a width to underlie the free outermost margin of the flap forming the inner facing, and an adhesive secures the third flap to at least some of the other three flaps to provide a rigid unitary structure.
 9. An insulated carton for storing and transporting cooled articles comprising side and bottom walls and a removable cover, the cover being hollow and formed by folding a fiberboard blank into a cover outer facing and four cover side walls, the first and second of which are at opposed sided and terminate as flaps folded inwardly to lie substantially in the plane of the inner face of the cover and the third of which terminates as a flap of a size substantially coextensive with the width and length of the cover so as to form the inner facing of the cover and the fourth terminates as a flap of a width to underlie the free outermost margin of the flap forming the inner facing, a polyurethane foam in the hollow of the cover and substantially filling the hollow and adhered to the inner surfaces of the outer facing, the side walls and the first and second flaps, a recess in the inner face of the body of foam representing in area a major portion of the area of the opening of the carton normally closed by the cover and in depth less than the thickness of the foam, a heat-absorbing body in said recess, a metal sheet overlying the recess and the margins of the foam surrounding the recess and immediately underlying the third flap to enclose and protect the contents of the recess, openings through the third flap exposing the metal sheet to the interior of the carton and representing in aggregate area from 25 to 75 percent of the cross-sectional area of the interior of the carton, and fasteners securing the third flap to the outer facing to provide a rigid unitary structure. 